Galectin-7 reprograms skin carcinogenesis by fostering innate immune evasive programs.

Non-melanoma skin cancer (NMSC) has risen dramatically as a result of chronic exposure to sunlight ultraviolet (UV) radiation, climatic changes and clinical conditions associated with immunosuppression. In spite of considerable progress, our understanding of the mechanisms that control NMSC development and their associated molecular and immunological landscapes is still limited. Here we demonstrated a critical role for galectin-7 (Gal-7), a ß-galactoside-binding protein preferentially expressed in skin tissue, during NMSC development. Transgenic mice (Tg46) overexpressing Gal-7 in keratinocytes showed higher number of papillomas compared to WT mice or mice lacking Gal-7 (Lgals7-/-) when subjected to a skin carcinogenesis protocol, in which tumor initiator 7,12-dimethylbenz[a]anthracene (DMBA) and tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA) were sequentially administered. RNAseq analysis of Tg46 tumor lesions revealed a unique profile compatible with cells of the myelomonocytic lineage infiltrating these tumors, an effect that was substantiated by a higher number of CD11b+Gr1+ cells in tumor-draining lymph nodes. Heightened c-Met activation and Cxcl-1 expression in Tg46 lesions suggested a contribution of this pathway to the recruitment of these cells. Remarkably, Gal-7 bound to the surface of CD11b+Ly6ChiLy6Glo monocytic myeloid cells and enhanced their immunosuppressive activity, as evidenced by increased IL-10 and TGF-ß1 secretion, and higher T-cell inhibitory activity. In vivo, carcinogen-treated Lgals7-/- animals adoptively transferred with Gal-7-conditioned monocytic myeloid cells developed higher number of papillomas, whereas depletion of these cells in Tg46-treated mice led to reduction in the number of tumors. Finally, human NMSC biopsies showed increased LGALS7 mRNA and Gal-7 protein expression and displayed transcriptional profiles associated with myeloid programs, accompanied by elevated CXCL1 expression and c-Met activation. Thus, Gal-7 emerges as a critical mediator of skin carcinogenesis and a potential therapeutic target in human NMSC.

Untangling Galectin-Mediated Circuits that Control Hypoxia-Driven Angiogenesis.

Development of an aberrant vascular network is a hallmark of the multistep pathological process of tumor growth and metastasis. In response to hypoxia, several pro-angiogenic factors are synthesized to support vascularization programs required for cancer progression. Emerging data indicate the involvement of glycans and glycan-binding proteins as critical regulators of vascular circuits in health and disease. Galectins may be regulated by hypoxic conditions and control angiogenesis in different physiopathological settings. These ß-galactoside-binding proteins may promote sprouting angiogenesis by interacting with different glycosylated receptors and triggering distinct signaling pathways. Understanding the role of galectins in tumor neovascularization will contribute to the design of novel anti-angiogenic therapies aimed at complementing current anti-cancer modalities and overcoming resistance to these treatments. Here we describe selected strategies and methods used to study the role of hypoxia-regulated galectins in the regulation of blood vessel formation.

[A functional platform to monitor SARS-CoV-2-specific T cell responses in vaccinated individuals and COVID-19 recovered patients]. / COVID-T: Una plataforma funcional para monitorear la respuesta de linfocitos T específicos de SARS-CoV-2 en individuos vacunados y recuperados de COVID-19.

The rapid spread of the SARS-CoV-2, the causative agent of the emergent pandemic disease COVID-19, requires the urgent commitment of the immunology community to understand the adaptive immune response developed by COVID-19 convalescent patients and individuals vaccinated with different strategies and schemes, with the ultimate goal of implementing and optimizing health care and prevention policies. Currently, assessment of SARS-CoV-2-specific immunity is mainly focused on the measurement of the antibody titers and analysis of their neutralizing capacity. However, a considerable proportion of individuals lack humoral responses or show a progressive decline of SARS-CoV-2-specific neutralizing antibodies. In order to study the cellular response of convalescent patients and vaccinated individuals, we have developed the "COVID-T Platform", an optimized strategy to study SARS-CoV-2-specific T cell responses. This platform allows assessment of the nature, magnitude and persistence of antigen-specific T-cell immunity in COVID-19-convalescent patients and vaccinated individuals. Moreover, it gives the opportunity to study cellular responses against emerging coronavirus variants and to identify individuals with cross-reactive immunity against seasonal coronaviruses.

La rápida propagación del coronavirus SARS-CoV-2, agente causal de la enfermedad pandémica emergente COVID-19 y sus nuevas variantes, requiere del compromiso de la comunidad inmunológica para comprender la magnitud y naturaleza de la respuesta inmunológica adaptativa desarrollada por pacientes recuperados de COVID-19 e individuos vacunados con diferentes estrategias y protocolos, a los fines de implementar nuevas políticas sanitarias. En la actualidad, la determinación de la inmunidad contra SARS-CoV-2 se basa principalmente en la detección de anticuerpos específicos y la determinación de su actividad neutralizante. Sin embargo, a pesar de la alta sensibilidad de estos ensayos, un número considerable de pacientes e individuos vacunados carecen de respuesta humoral detectable, o evidencian una disminución rápida de la misma en el tiempo. Con el objetivo de estudiar la respuesta inmune celular desencadenada frente a SARS-CoV-2, en nuestro laboratorio desarrollamos la "Plataforma COVID-T" estrategia integral optimizada dirigida a caracterizar y monitorear la respuesta de linfocitos T específicos de SARS-CoV-2 a partir de muestras de sangre de individuos vacunados y/o recuperados de COVID-19. Esta plataforma permite evaluar la naturaleza, magnitud y persistencia de la inmunidad celular T generada tanto por la infección con SARS-CoV-2, como por distintos esquemas y protocolos de vacunación en diferentes poblaciones de individuos. Asimismo, permite evaluar la respuesta inmunológica T generada frente a nuevas variantes del virus e identificar individuos sanos resistentes a SARS-CoV-2 con inmunidad pre-existente hacia coronavirus estacionales.

COVID-T: una plataforma funcional para monitorear la respuesta de linfocitos t específicos de SARS-COV-2 en individuos vacunados y recuperados de COVID-19 / COVID-T: A functional platform to monitor SARS-CoV-2-specific T cell responses in vaccinated individuals and COVID-19 recovered patients

Resumen La rápida propagación del coronavirus SARS-CoV-2, agente causal de la enfermedad pandémica emergente COVID-19 y sus nuevas variantes, requiere del compromiso de la comunidad inmunológica para comprender la magnitud y naturaleza de la respuesta inmunológica adaptativa desarrollada por pacientes recuperados de COVID-19 e individuos vacunados con diferentes estrategias y protocolos, a los fines de imple mentar nuevas políticas sanitarias. En la actualidad, la determinación de la inmunidad contra SARS-CoV-2 se basa principalmente en la detección de anticuerpos específicos y la determinación de su actividad neutralizante. Sin embargo, a pesar de la alta sensibilidad de estos ensayos, un número considerable de pacientes e indivi duos vacunados carecen de respuesta humoral detectable, o evidencian una disminución rápida de la misma en el tiempo. Con el objetivo de estudiar la respuesta inmune celular desencadenada frente a SARS-CoV-2, en nuestro laboratorio desarrollamos la "Plataforma COVID-T" estrategia integral optimizada dirigida a caracte rizar y monitorear la respuesta de linfocitos T específicos de SARS-CoV-2 a partir de muestras de sangre de individuos vacunados y/o recuperados de COVID-19. Esta plataforma permite evaluar la naturaleza, magnitud y persistencia de la inmunidad celular T generada tanto por la infección con SARS-CoV-2, como por distintos esquemas y protocolos de vacunación en diferentes poblaciones de individuos. Asimismo, permite evaluar la respuesta inmunológica T generada frente a nuevas variantes del virus e identificar individuos sanos resistentes a SARS-CoV-2 con inmunidad pre-existente hacia coronavirus estacionales.

Abstract The rapid spread of the SARS-CoV-2, the caus ative agent of the emergent pandemic disease COVID-19, requires the urgent commitment of the immunology community to understand the adaptive immune response developed by COVID-19 convalescent patients and individuals vaccinated with different strategies and schemes, with the ultimate goal of implementing and optimizing health care and prevention policies. Currently, assessment of SARS-CoV-2-specific immunity is mainly focused on the measurement of the antibody titers and analysis of their neutralizing capacity. However, a considerable proportion of individuals lack humoral responses or show a progressive decline of SARS-CoV-2-specific neutral izing antibodies. In order to study the cellular response of convalescent patients and vaccinated individuals, we have developed the 'COVID-T Platform', an optimized strategy to study SARS-CoV-2-specific T cell responses. This platform allows assessment of the nature, magnitude and persistence of antigen-specific T-cell immunity in COVID-19-convalescent patients and vaccinated individuals. Moreover, it gives the opportunity to study cellular responses against emerging coronavirus variants and to identify individuals with cross-reactive immunity against seasonal coronaviruses.

Reprogramming the tumor metastasis cascade by targeting galectin-driven networks.

A sequence of interconnected events known as the metastatic cascade promotes tumor progression by regulating cellular and molecular interactions between tumor, stromal, endothelial, and immune cells both locally and systemically. Recently, a new concept has emerged to better describe this process by defining four attributes that metastatic cells should undergo. Every individual hallmark represents a unique trait of a metastatic cell that impacts directly in the outcome of the metastasis process. These critical features, known as the hallmarks of metastasis, include motility and invasion, modulation of the microenvironment, cell plasticity and colonization. They are hierarchically regulated at different levels by several factors, including galectins, a highly conserved family of ß-galactoside-binding proteins abundantly expressed in tumor microenvironments and sites of metastasis. In this review, we discuss the role of galectins in modulating each hallmark of metastasis, highlighting novel therapeutic opportunities for treating the metastatic disease.

Tissue-specific control of galectin-1-driven circuits during inflammatory responses.

The relevance of glycan-binding proteins in immune tolerance and inflammation has been well established, mainly by studies of C-type lectins, siglecs and galectins, both in experimental models and patient samples. Galectins, a family of evolutionarily conserved lectins, are characterized by sequence homology in the carbohydrate-recognition domain, atypical secretion via an endoplasmic reticulum-Golgi-independent pathway and by the ability to recognize ß-galactoside-containing saccharides. Galectin-1 (Gal-1), a prototype member of this family, displays mainly anti-inflammatory and immunosuppressive activities, although, similar to many cytokines and growth factors, it may also trigger paradoxical pro-inflammatory effects under certain circumstances. These dual effects could be associated to tissue-, time- or context-dependent regulation of galectin expression and function, including particular pathophysiologic settings and/or environmental conditions influencing the structure of this lectin, as well as the availability of glycosylated ligands in immune cells during the course of inflammatory responses. Here, we discuss the tissue-specific role of Gal-1 as a master regulator of inflammatory responses across different pathophysiologic settings, highlighting its potential role as a therapeutic target. Further studies designed at analyzing the intrinsic and extrinsic pathways that control Gal-1 expression and function in different tissue microenvironments may contribute to delineate tailored therapeutic strategies aimed at positively or negatively modulating this glycan-binding protein in pathologic inflammatory conditions.